Conventionally, in manufacturing an organic resin coated metal sheet which forms a resin film on a metal sheet by extruding an organic resin to a surface of the metal sheet using a T-die, with respect to the treatment applied to both edge portions (ear portions) of a resin film whose thicknesses are increased due to a neck-in phenomenon generated after the extrusion of the resin from the T-die, there has been known a technique in which the resin film forms the ear portions on both sides of the organic resin coated metal sheet and, thereafter, the ear portions are trimmed together with a metal sheet having an area of necessary minimum. Alternatively, a resin film is applied to a metal sheet by coating while sufficiently increasing a width of the metal sheet so as to prevent the formation of ear portions and, thereafter, the resin film is trimmed together with both edge portions of the metal sheet having a width corresponding to the expansion of the width of the metal sheet.
However, the former method has a drawback that the ear portion falls in a path before arriving at a trimming step or is entangled in and is adhered to a base material, while the latter method has a drawback that portions of the resin film having a large thickness cannot be used and hence, the use efficiency of the metal sheet is decreased.
Further, both methods have a drawback that the trimmed resin film is integrally formed with the metal sheet and hence, the trimmed resin film cannot be used for recycling.
In view of the above, to overcome the above-mentioned drawbacks, there has been also proposed a method which recycles ear portions of a resin film after trimming as disclosed in the following patent document 1.
According to this method, in extruding a molten resin to a metal sheet from a T-die and applying a resin film to a metal sheet by sandwiching the molten resin and both surfaces of the metal sheet between a pair of laminate rollers, ear portions which project from the metal sheet in the widthwise direction of the metal sheet are clamped, torn and removed by a grip means such as endless guide belts before the resin is cooled.
Patent Document 1